This invention is directed to copper salts of hindered phenol substituted succinic anhydride derivatives and to lubricant compositions containing minor amounts thereof.
The use of hindered phenols for their antioxidant properties in a variety of products including food materials, rubbers, plastics, and lubricants is well known.
The use of copper carboxylates such as copper oleate has been reportedly useful as an antioxidant, European Pat. No. 92946, and as an engine oil antioxidant, British Pat. No. 2,056,482.
The use of copper salts of succinic anhydride derivatives as effective antioxidants for crankcase lubricants without the deleterious effect on rust and copper/lead bearing corrosion performance that accompanies copper oleate; and the use of carboxylates as antirust and anticorrosion additives in lubricants has been well documented and includes derivatives of oleic acid and oleoyl sarcosine are for example described in European Pat. No. 149,549 and U.S. Pat. No. 4,552,677.
There is an ongoing search for new and better lubricant additives, additives capable of fulfilling the ever-increasing demands of the lubricant art.
It has now been found that the use of the novel copper alkenyl succinic acid derived hindered phenols disclosed herein provide exceptional multifunctional antioxidant activity, with anticorrosion properties. The antioxidant activity demonstrated is greater than that reported for the corresponding copper carboxylates or hindered phenols.
These remarkable benefits are available for a variety of synthetic and mineral oil based lubricants or mixture of mineral and synthetic oils. The lubricant may also be a grease prepared from such oils. To the best of our knowledge, these compositions have not been previously used as antioxidants in lubricating oils, greases or fuels. It is also believed that these additive materials would be highly useful in polymers as stabilizers.
Typical synthetic oils include but are not limited to polyisobutylene, polybutenes, hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, trimethylol propane esters, neopentyl and pentaerythritol esters, di(2-ethylhexyl)sebacate, di(2-ethylhexyl)adipate, dibutyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenols, siloxanes and silicones (polysiloxanes), alkyl-substituted diphenyl ethers typified by a butyl-substituted bis-(p-phenoxyphenyl)ether, phenoxy phenylether, etc. Mineral oils suitable herein include oils of lubricating viscosity ranging from about 45 SSU at 100.degree. F. to about 250 SSU at 210.degree. F. or any other suitable oil of lubricating viscosity.